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S.cerevisiae progenitors

Jon Binkley binkley at fafner.Stanford.EDU
Tue Jul 29 15:52:17 EST 1997


Dennis Walker wrote:

>I am not a scientist! I am an amateur brewer trying to recreate
>a medieval beer recipe from 16th century England as closely as possible.
>	I know it is probably hopeless to try to duplicate the yeast 
>strains that might have been in use then, but I would like to try to get 
>a little closer than ripping open a packet of modern engineered brewers' 
>yeast. 
>	I have tried to find a source of supply or guidance towards same 
>for any S. cerevisiae progenitor strains that might exist representative 
>of 'unengineered' brewing yeast. I am totally lost on a sea of web sites 
>discussing genome projects and other 'cutting-edge' topics.
>	I guess what I'm looking for is the 'trailing edge.' I would 
>appreciate any suggestions. Thanks for your time.

As has been pointed out, most brewing strains have not been "engineered"
very much, if by that you mean genetically engineered.  Some of the 
very large brewers are doing it to introduce desirable traits such as
alcohol tolerance, flocculance, and the ability to metabolize a wider
variety of carbohydrates, but most breweries stick with the same cultures
that have worked for them for tens or hundreds of years.

The type of ale you want to recreate was made before yeast was discovered,
and was probably fermented by adding a portion of old ale into the
new.  This probably contained a wide variety of yeast and bacteria in
addition to Saccharomyces.  It probably tasted sour from the bacteria,
and probably tasted somewhat "horsey" from a very common wild yeast
called Brettanomyces.  In other words, it probably tasted very much
like a beer style called "Lambic" that is still brewed in Belgium in 
same way it always has been--by spontaneous fermentation.

Recommendations:

Culture the dregs from a bottle of lambic.  I recommend Boon Geuze.
Leifman's is also good.  Only use Lindemann's if all else fails.
Be sure and taste some Geuze (unflavored lambic) before you make
too much of your own.  You might not want to be quite as authentic
as you originally intended (I love the stuff, personally).

Some brewing yeast labs have purified some of the major constituant
bugs from lambic cultures, which you can buy from homebrew supply
retailers.  Word on the street is that these are rarely as successful
as simply coming from a bottle of lambic.

Read the newsgroup rec.crafts.brewing.  This type of thing is right
up their alley.

Check out the web site: http://realbeer.com/brewery/index.html
Lots of good references and recipes there.





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